There has been known a pressure regulation valve in a control device of a vehicle, which regulates or controls an oil pressure supplied to a clutch. When decrease in a clutch pressure (the oil pressure) controlled by this pressure regulation valve is detected during travel or during vehicle stop, the control device of the vehicle changes a command pressure (a signal pressure) to the pressure regulation valve from the solenoid and moves the spool valve provided inside the pressure regulation valve (a foreign matter removal control) in a vehicle stop state (during the vehicle stop). With this operation, it is possible to drain or remove contamination trapped in the pressure regulation valve (see, for instance, Patent Document 1).
In the conventional control device of the vehicle, however, since the contamination is drained in the vehicle stop state by moving the spool valve, for instance, in a case where the clutch pressure decreases due to the trap of the contamination in the pressure regulation valve during the travel, the decrease in the clutch pressure during the travel cannot be prevented during the travel. On the other hand, if the conventional foreign matter removal control is carried out during the travel, for instance, in a case where the spool valve is moved to a side where a discharge pressure of the pressure regulation valve is decreased, an oil pressure at a downstream side with respect to the pressure regulation valve is decreased, and this affects a vehicle travelling state, such as insufficient oil pressure supply to the clutch or a belt etc. As described above, the conventional control device of the vehicle has a problem of not being able to prevent the decrease in the clutch pressure during the travel without affecting the vehicle travelling state when the clutch pressure decreases during the travel.